Showing papers by "Sumio Shinoda published in 2022"
TL;DR: The two pandemics, COVID-19 and Spanish flu are compared and discussed, with the high rates in developed countries, such as the US and those in Europe, which have aging societies, and low rates in developing countries, where the population is largely young.
Abstract: We are still in the early stage of 21st century and the two pandemics Spanish flu and COVID-19 are the presentative pandemics in 20th and 21st centuries, respectively. The Spanish flu pandemic raged from 1918 to 1920, just after World War I. It was the first influenza pandemic worldwide; since then, humankind has experienced many such pandemics. Spanish flu is caused by a virus. However, since virology was not well established at that time, the new clinical system was needed to cope with “unknown pathogen”; during the pandemic, high infection rates were recorded, but our predecessors managed to somehow tackle the situation. With respect to the ongoing COVID-19 pandemic, both the virus and its genome were clarified quickly. Nonetheless, it has turned out to be quite an intriguing infectious disease, with the high rates in developed countries, such as the US and those in Europe, which have aging societies, and low rates in developing countries such as those in Africa, where the population is largely young. Here, I compared and discuss the two pandemics, COVID-19 and Spanish flu.
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TL;DR: HapR mutations had a strong influence on biofilm formation and that sequence polymorphisms leading to the disruption of DNA-binding sites or dimerization of the HapR will result in more-robust V. cholerae biofilms.
Abstract: Our study revealed an ancestral hapR sequence from a phylogenetic reconstruction that displayed the evolutionary lineage of the nonpandemic to the pandemic strains. Here, we established hapR1 and hapR2 as major hapR haplogroups. ABSTRACT We investigated the influence of hapR sequence mutations on the biofilm formation of Vibrio cholerae. In this study, hapR sequences from 85 V. cholerae strains belonging to both pandemic and nonpandemic serogroup were investigated through phylogenetic and sequence analyses. Biofilm formation assays under aerobic and anaerobic conditions were also performed. Sequence variations include single point mutations and insertions/deletions (indels) leading to either truncated or frameshifted HapR. Population structure analysis revealed two major hapR haplogroups, hapR1 and hapR2. Phylogenetic reconstruction displayed a hypothetical ancestral hapR sequence located within the hapR1 haplogroup. Higher numbers of single nucleotide polymorphisms and genetic diversity indices were observed in hapR1, while indels occurred dominantly in hapR2. Aerobic conditions supported more robust biofilms compared to anaerobic conditions. Strains with frameshifted HapR produced the largest amount of biofilm under both oxygen conditions. Quantitative real-time PCR assay confirmed that strains with truncated and frameshifted HapR resulted in a nonfunctional regulator as exhibited by the significantly low hapA gene expression. The present study shows that HapR mutations had a strong influence on biofilm formation and that sequence polymorphisms leading to the disruption of DNA-binding sites or dimerization of the HapR will result in more-robust V. cholerae biofilms. IMPORTANCE Our study revealed an ancestral hapR sequence from a phylogenetic reconstruction that displayed the evolutionary lineage of the nonpandemic to the pandemic strains. Here, we established hapR1 and hapR2 as major hapR haplogroups. The association of the O1 and O139 serogroups with the hapR2 haplogroup demonstrated the distinction of hapR2 in causing cholera infection. Moreover, mutations in this regulator that could lead to the disruption of transcription factor-binding sites or dimerization of the HapR can significantly affect the biofilm formation of V. cholerae. These observations on the relationship of the hapR polymorphism and V. cholerae biofilm formation will provide additional considerations for future biofilm studies and insights into the epidemiology of the pathogen that could ultimately help in the surveillance and mitigation of future cholera disease outbreaks.